Spirit level

ABSTRACT

A spirit level with a pair of elongate arms which are pivotable relative to each other about a pivot axis and which have a measuring device, for being placed on a plane and for detecting an inclination thereof, wherein each of the arms has a first and a second longitudinal portion with a bend portion connecting same, a longitudinal axis of the first longitudinal portion of each arm extended in a direction parallel to a longitudinal axis of the associated second longitudinal portion. The pivot axis extends in the regions of the bend portion of the arms. The first longitudinal portions of the two arms are of a substantially equal first length and the second longitudinal portions of the two arms are of a substantially equal second length.

This invention relates generally to a spirit level and, morespecifically, to a dual-armed spirit level for determiningtwo-dimensional inclination with respect to a plane.

Such a spirit level of the general kind set forth is known from DE 35 26018 A1. Spirit levels have a wide area of use, for example in structuralengineering and in mechanical engineering, and serve to check theposition of vertical and horizontal components.

A conventional spirit level comprises a wood or metal strip ofsubstantially rectangular cross-section, which is provided with at leastone level. Hereinafter the term level is used to denote a slightlycurved glass tube (tube level) or a glass capsule with slightlyspherical top (circular spirit level) which are filled except for a gasbubble with alcohol, ether or another liquid. When the level is in ahorizontal position that gas bubble is disposed precisely at the centrethereof.

Such spirit levels which only comprise one strip can only be used todetermine inclination in one direction (that is to sayone-dimensionally), whereby problems can be involved in aligning planesor surfaces, for example a table top. In such a case the above-describedconventional spirit levels can provide a remedy by virtue of adopting aprocedure whereby firstly the inclination of the plane is checked andset in a first direction and thereupon the inclination of the plane ischecked and set in a second direction, with the first and seconddirections generally being perpendicular to each other. However such aprocedure is made difficult not least by virtue of the fact that usuallyadaptation of the inclination of the plane in respect of the firstdirection inevitably also involves a change in the inclination of theplane in the second direction so that an alignment process becomes arecursive and lengthy procedure which, besides the amount of timeinvolved, achieves a correspondingly low level of accuracy.

Now, spirit levels are known from the state of the art, which permittwo-dimensional determination of inclination, that is to say withrespect to a plane.

Thus DE 35 26 018 A1 disclosing the general kind of apparatus involvedhas an elongate main body of rectangular cross-section on which asmaller arm is centrally pivotably arranged. When the arm is in theoutwardly pivoted condition it is therefore possible to provide fortwo-dimensional determination of inclination.

However that spirit level in accordance with the state of the art is notonly structurally expensive and disadvantageous--the arm must bedesigned to be precisely aligned to be received in a suitable recess inthe main body and production of the pivot or hinge axis is as a resultinevitably complicated or imperfect--but also that known spirit level isdisadvantageous in regard to accuracy and further measurementproperties: the fact that the pivotable arm is completely received inthe associated recess in the main body necessarily means that the spiritlevel, along the main body, is of a greater length than the arm. Ashowever the degree of measuring accuracy of a spirit level is influencedby the spacing of a level provided at the end of an arm relative to thecentral point, the spirit level which is known in accordance with thegeneral kind set forth with levels disposed at each of its respectiveends and thus arranged at different spacings relative to the axialcentre, is inaccurate in regard to its measuring accuracy between thearms and is thus inevitably disadvantageous.

Furthermore the spirit level of the general kind set forth evidentlypermits it to be put only on to a continuous plane for the fact that therecess for the arm, which is formed almost entirely along the undersideof the main body, means that the spirit level must be put on to thesubjacent plane or surface, at both end portions of the main body, inorder to be able to perform any measurement procedure at all. If howeverfor example the situation involves ascertaining the slope of a plane ora surface which in terms of its dimensions is smaller than the spacingof the end portions of the main body, the spirit level of the generalkind set forth is unsuitable for such use.

FR 2 613 475 also discloses a spirit level which is formed from astar-like arrangement of three angle members which are arranged relativeto each other rigidly at an angle of 120°. Besides the increasedexpenditure from the point of view of construction and manufacture,which the production of such an apparatus involves, a spirit level ofthat kind is already disadvantageous for the simple reason that it canonly be accommodated with difficulty in terms of the amount of spaceoccupied and in particular does not readily fit into a tool box or thelike. Accordingly mobile and flexible use on site is made markedly moredifficult with such an item of equipment.

Therefore the object of the present invention is to provide a spiritlevel which enjoys enlarged and more flexible possible uses and which inaddition is simple to manufacture while being suitable for massproduction and which takes up only a small amount of space.

The object of the present invention is achieved using an arrangement fora spirit level in which the arms are pivotable relative to each other inthe region of the respective bend portion and each have a first and asecond longitudinal portion connected by the rigid bend portion permitthe spirit level to be collapsed in a simple manner which saves space.By virtue of the substantially equal lengthwise dimension of therespective longitudinal portions of the arms, the arms afford theprerequisite for two-dimensional measurement which is of equal accuracyin each direction in the outwardly pivoted condition. At the same timethe arrangement ensures that both in the collapsed condition and alsowith any angle of pivotal interrelationship between the arms, there isalways a continuous contact with a subjacent surface so that the spiritlevel according to the invention is suitable for measuring anyplanes--continuous plates or panels, troughs or edges etc--of anydimensions.

Advantageous developments of the invention are described in theappendant claims.

In the present invention, the configuration of the first and secondlengths results in complete symmetry which--for example for theproduction of a high-precision measurement instrument--permits theprovision of a level at each end of an arm and thus in each measurementdirection can carry two measurement devices which are respectivelyspaced at a constant spacing. In a particularly preferred feature thewidth of the longitudinal portions of each arm corresponds to thedisplacement afforded by the bend portion (that is to say the spacing ofthe longitudinal axis of the first longitudinal portion with respect tothe longitudinal axis of the associated second longitudinal portion in aplane) thereby affording the prerequisite that both arms can be fittedone into the other for pivotal movement thereof and the entirearrangement, in the condition of being folded or pivoted together, isonly of a total width which corresponds to two arms in a condition ofbearing against each other. In that way it is possible to produce aspirit level which requires a minimum amount of space.

In a particularly suitable configuration each arm is provided in theregion of the bend portion with a recess which is of such a dimensionthat the bend portion of the respective other arm fits into same.

In a particularly advantageous feature from the production procedurepoint of view, both arms are of the same external shape so that they canbe produced--in a particularly preferable feature additionally in anintegral configuration--by means for example of an injection mouldingprocedure by means of the same injection moulding tool. Although thespirit level according to the invention is a precision tool, it istherefore possible in that way to provide for comparatively inexpensivemanufacture.

In accordance with a further preferred development of the invention atleast one of the arms is adapted to be divisible along its longitudinaldirection to receive an extension portion or the like and/or at its endhas a device with which the arm can be additionally extended, forexample by a conventional spirit level. A possible area of use for sucha development would involve measuring or adjusting a frame or aperipherally extending edge, the dimensions of which are larger thanthose of the spirit level in the non-extended condition. By inserting orattaching suitable extensions however it is then possible to bridge overa correspondingly large internal space of a frame or a tub or tank.

While the spirit level according to the invention--as in theconventional case--can be of a solid configuration or can be in the formof a hollow profile of substantially rectangular cross-section, it hasbeen found particularly advantageous for at least the longitudinalportions of the arms to be produced by a single U-shaped profile or adouble T-shaped profile. Such a profile configuration is in that respectnot only advantageous in terms of simple and inexpensive manufacture,but it also permits the arms to be produced with a substantiallytorsionally stiff structure in a configuration which is true to shapeand is therefore accordingly particularly suitable for an accurate andreliable measuring apparatus like the spirit level according to theinvention.

In accordance with a particularly preferred development the arms whichare pivotable relative to each other can be latched or locked relativeto each other at predetermined spacings--for example 45° or 90°--so thatin practical use accidental displacement thereof can be prevented. In aparticularly preferred feature moreover the spirit level according tothe invention is provided in the region of the pivot axis between thearms to be pivoted with a circular spirit level and/or a scale as ameasuring device for a set angle between the arms.

Depending on the specific area of use involved, the spirit levelaccording to the invention can be provided as required with levels forhorizontal or vertical measurement, which can preferably be fitted intosuitable recesses in the arms. In a particularly suitable constructionthe arms can additionally be provided with a height measuring deviceand/or a length measuring device, for example a length scale which isprinted thereon. The various advantageous configurations of the armswith outside surfaces of large area additionally advantageously permitthe spirit level according to the invention to be provided with companyidentifications, advertising printing thereon, operating instructions orthe like.

It will be appreciated that instead of the known tube-type or circularlevels, it is also possible to use electronic position sensors, forexample with a digital display.

Further advantages, features and details of the invention will beapparent from the following description of preferred embodiments andwith reference to the drawing in which:

FIG. 1 is a perspective view of the spirit level in accordance with afirst embodiment,

FIG. 2 is a plan view of the spirit level shown in FIG. 1,

FIG. 3 is a perspective view of the hinge portion of the spirit levelshown in FIG. 1,

FIG. 4 is a side view of a limb of the hinge portion of a spirit levelas shown in FIG. 1 with two arms fitted thereon,

FIG. 5 is a view in longitudinal section through an end portion of anarm which is fitted on to a limb of the hinge portion shown in FIG. 3,

FIG. 6 is an exploded view of an arm of a spirit level of the firstembodiment with an extension portion,

FIG. 7a is a perspective view of a spirit level in accordance with thefirst embodiment, which is provided with a roll-up retractable tapemeasure,

FIG. 7b is a perspective view of a spirit level in accordance with thefirst embodiment, which is provided with an electronic distancemeasuring device,

FIG. 8 is a perspective view of a hinge portion of a spirit level inaccordance with a second embodiment,

FIG. 9 is a side view of a limb of a hinge portion of a spirit level inaccordance with the second embodiment, to which two conventional spiritlevels are fixed,

FIG. 10 is a perspective view of a spirit level in accordance with thesecond embodiment,

FIG. 11 is a plan view of a spirit level as shown in FIG. 10,

FIG. 12 is a perspective view of a spirit level in accordance with thethird embodiment,

FIG. 13 is a plan view of a spirit level as shown in FIG. 12, and

FIG. 14 is a side view of a limb of a spirit level as shown in FIG. 13.

The central hinge portion 1 of the spirit level is composed of twomutually crossing limbs 2 (see FIG. 3). Each of those limbs 2 issubdivided into a central hinge part 3 of approximately circular shapein plan and two outer connecting parts 4. The two connecting parts 4 ofa limb 2 extend parallel to each other. They are laterally displacedrelative to each other by the width of a connecting part 4. The insidesurfaces 7 of the two connecting parts 4 of a limb 2 lie on a commonplane which extends through the hinge axis 8 (see FIGS. 2, 11 and 13).At least one of the two limbs 2 carries at the outer end of its hingepart 3 a circular spirit level which permits checking of the slope of aplane in all directions (see FIGS. 3 and 8).

The limbs 2 of the hinge portion 1 are preferably made from aluminium orplastic material.

For the purposes of measuring angles with respect to the vertical orhorizontal, disposed on the outer end of at least one of the limbs 2 ofthe hinge portion 1 is a measuring scale 15 with angle graduations (seeFIG. 3). The measuring scale 15 extends over at least 90°. Theconnecting part 4 which directly adjoins the measuring scale 15 isprovided with a marking 16 which points to the respectively applicablemeasurement value of the scale 15.

In the case of the spirit level of the first embodiment each connectingpart 4 is in turn subdivided into a guide part 5 which is towards thehinge part 3 and a fitment part 8 which is remote from the hinge part 3(see FIG. 3). The guide part 5 is of an approximately trapezoidalconfiguration in plan and is of a rectangular side elevation. Thefitment parts 6 are in the form of hollow profiles of rectangularconfiguration in plan and with a rectangular side elevation.

Each arm 9 of a spirit level of the first embodiment is formed by ahollow profile of rectangular cross-section. The hollow profile, maycomprise aluminium or plastic material. A respective one of the fourarms 9 is fitted on to each fitment part 6 of the limbs 2 (see FIG. 4).That is made possible by virtue of the fact that the internalcross-section of the hollow profile of an arm 9 corresponds to theexternal cross-section of the fitment part 6 of the limbs 2. The hollowprofile of an arm 9 can therefore completely accommodate in its interiora fitment part 6 of a limb 2 (see FIG. 5). The arms 9 can beadditionally fixed to the fitment parts 6 by at least one screw (notshown).

The outer end of the arms 9 is closed. Two of the four arms 9 have intheir outer end portion at the top side thereof a recess of rectangularside elevation. Each of those recesses accommodates a tube level whosetube extends parallel to the longitudinal axis 11 of the correspondingarm 9. The tube levels 10 serve to check a horizontal plane. Thehorizontal measuring levels are preferably mounted on two arms 9 whichare fixed to different limbs 2 (see FIGS. 1 and 2).

The two arms 9 without horizontal measuring levels have in each of theirouter end portions a continuous recess which extends at a right angle tothe side surfaces 13 of the corresponding arm 9 and which is preferablyof a square side elevation. Arranged in each of those recesses there isalso a respective tube level 10 whose tube extends however at a rightangle to the longitudinal axis 11 of the arm 9 (see FIGS. 1 and 4).Those tube levels 10 serve to check vertical planes.

So that the spirit level can be hung up, two adjacent arms 9 are eachprovided with a respective through bore 14 which extends at a rightangle to the side surfaces 13 of the arms 9 (see FIGS. 1 and 4). Thebores 14 are disposed at mutually corresponding positions on the twoarms 9 so that they are aligned with each other when the arms 9 bearagainst each other with their side surfaces 13.

In a preferred embodiment the height of the spirit level is 50 mm andits width is 40 mm when it is in the condition of being collapsed. Thereare provided various lengths which can be in the range of 200 to 2000mm.

By virtue of the push-on connection between the central hinge portion 1and the arms 9, the various lengths can be afforded by the use of arms 9of different lengths. The hinge portion 1 preferably remains unchanged.

There is also the possibility of providing the different lengths bymeans of extension portions 17 (see FIG. 6). Those extension portions 17are inserted between the arms 9 and the hinge portion 1. An extensionportion 17 is divided into a main body and a fitment part 18. The mainbody comprises a hollow profile which is of the same cross-section andthe same wall thickness as the hollow profile of the arms 9. The fitmentpart 18 also comprises a hollow profile which however is of the samecross-section and the same wall thickness as the hollow profile of thefitment parts 18 on the hinge portion 1. Each extension portion 17 isfitted with its main body on to a fitment part 18 of the hingeportion 1. The fitment part 18 of each extension portion 17 is fittedinto an arm 9.

A distance measuring device 19, 20 can be disposed in the outer endportion of at least one arm 9 (see FIGS. 7a and 7b).

This may involve a mechanical distance measuring device 19 or anelectronic distance measuring device 20. FIG. 7a shows a spirit levelwith a mechanical distance measuring device 19 in the form of a roll-upretractable tape measure 21. In the retracted condition the tape measure21 is disposed, except for a short end portion thereof, in the interiorof the arm 9. It can be pulled out through an opening at a narrow sideof the arm 9. A spring is stressed when the tape measure is pulled out.When the tape measure 21 is no longer needed, the spring force is usedto roll up the tape measure 21 again in the interior of the arm 9. Therolling-up procedure can be started by means of a release button 23. Thedistance defined by the length of the portion of tape measure which ispulled out is indicated in a viewing window 22 arranged at that narrowside which is disposed opposite the exit opening for the tape measure21.

The mechanical distance measuring device can also be in the form of asimple roll-up tape measure without viewing window and release button.

The electronic distance measuring device 20 can operate for example withlight, ultrasound or micro-waves. Those waves serve as a carrier formeasuring signals which are modulated thereon. After reflection at thetarget point, the distance is calculated from the signal transit timeand the speed of propagation. Such apparatuses are known from themeasuring art.

The distance measuring device 20 is disposed entirely in the interior ofan arm 9. The measuring operation can be triggered off with an operatingknob or button 25 arranged for example at the outer end of thecorresponding arm 9. The measuring result is indicated by a displaydevice 24 which is disposed for example on a narrow side of the arm 9.The opening for the emitted or reflected waves respectively to passthrough is disposed at the opposite narrow side. Batteries which arealso disposed in the interior of the arm 9 can serve as the power sourcefor the distance measuring device 20.

In the case of the spirit level of the second embodiment each connectingpart 4 is divided into a guide part 5 which is towards the hinge part 3and a fixing device 26 which is remote from the hinge part 3 (see FIGS.8 and 11). The guide part 5 is of the same configuration as in the caseof the spirit level of the first embodiment. A conventional bar-likespirit level 28 can be fixed to each connecting part 4 by means of thefixing device 26, in such a way that an end of the conventional spiritlevel 28 is towards the outer end of the connecting part 4 and thecentral longitudinal axes of the conventional spirit level 28 and theconnecting part 4 are disposed on each other. The fixing device 26 canbe for example in the form of two fixing plates 27 which project at aright angle from the end of the guide part 5 (see FIG. 8). The outerside surface of each fixing plate 27 is flush with one of the two sidesurfaces of the guide part 5 and the two fixing plates 27 are at acertain spacing from each other. The end part of a conventional spiritlevel 28 is inserted from the outer end into the intermediate spacebetween the two fixing plates 27 (see FIGS. 10 and 11). Each fixingplate 27 is provided with two round bores 29. The bores 29 of the twofixing plates 27 of a fixing device 26 are aligned with each other inpairs. The end part of the conventional spirit level 28 is provided alsowith two transverse bores (not shown) passing therethrough. When the endpart is inserted each of those bores is aligned with a respective bore29 in each of the two fixing plates 27. The conventional spirit level 28is now fixed to the fixing device 26 by a screw 30, a bolt or a cotteror split pin being passed transversely through the respectively mutuallyaligned bores in the fixing plates 27 and the spirit level end part (seeFIGS. 9 to 11).

Finally there is also provided a third embodiment which differs from thefirst embodiment in that, in a simplifying construction, the arms 9 arenot fixed by means of push-on fitment connections to the limbs 2 of thehinge portion 1, but form therewith an interconnected unit. Each twoparallel arms 9 are therefore made in one piece together with the limbs2 of the hinge portion 1, which are disposed therebetween (see FIGS. 12to 14). This embodiment is considered as the mode of carrying theinvention into effect.

In addition the spirit level of the third embodiment may also beprovided with mechanical or electronic distance measuring devices 19, 20(not shown).

Both in the case of the spirit level of the first embodiment and thespirit level of the third embodiment, there is the possibility of usingelectronic position sensors with digital display (not shown), instead ofthe tube levels and circular spirit levels.

In accordance with an alternative configuration of the above-describedembodiment it is possible for the arms of the spirit level to be of aU-shaped or double-T-shaped profile in cross-section. Such aconfiguration--particularly if aluminium is used in a die castingprocess--simplifies production and permits the surfaces to be of aprecise and dimensionally true nature. That configuration for the armsin the form of U-shaped or double-T-shaped profiles is not illustratedin the figures.

In accordance with a further preferred development of the invention allthree embodiments as described above may be provided in the hingeportion 1 with a retaining or latching means (not shown) which, atpredetermined angular spacings, for example 30°, 45° or 90°, permits thearms which are pivoted relative to each other to be arrested or latchedat that predetermined angle and thus prevents unintended displacement ofthe arms in use of the spirit level.

In accordance with still a further preferred development the mountingarrangement in the hinge portion 1 is afforded by means of an axialneedle bearing which is parallel to the hinge axis. That makes itpossible to provide for particularly precise mounting of the arms toeach other. In addition the hinge portion can preferably be madewater-tight by means of a silicone ring or the like so that the spiritlevel according to the invention can also be used in a damp environmentwithout the risk of corrosion.

The proposed spirit level according to the invention is employed or usedin the following manner:

To check a plane, the arms 9 of the spirit level are pivoted outwardlyfrom each other. The ideal angle of opening depends in that respect onthe size of the plane to be checked.

Thereafter the spirit level is put on to the horizontal or verticalplane to be checked. The plane can now be simultaneously adjusted in twodirections by means of the two horizontal and vertical measuring levelsrespectively.

If at the same time the distance of the plane to be checked in relationto a second plane or a fixed point is also to be ascertained, then thespirit level is applied to the plane to be checked, in such a way thatthat arm end part which includes the distance measuring device 19, 20projects beyond the edge of the plane. Distance measurement can now beeffected by pulling out the tape measure 21 or by triggering off theelectronic measuring procedure.

Moreover the spirit level can be used for aligning a rectangular plateor panel simultaneously in the vertical and also in the horizontal. Forthat purpose the spirit level is opened at an angle of 90°. One of thearms 9 with a horizontal measuring level is then applied to the upperhorizontal narrow side of the plate or panel and one of the arms 9 witha vertical measuring level is applied to a vertical narrow side. Thenarrow sides can now be adjusted simultaneously horizontally andvertically respectively by means of the spirit level.

It is also possible to use the spirit level to measure angles of up to90° or complementary angles of up to 180°. It is thus also possible toadjust planes which are inclined with respect to the vertical andhorizontal at a desired angle of inclination. By virtue of the anglemeasuring device, the proposed spirit level can also be used formeasuring angles.

Correct adjustment of the spirit level can be easily checked by thespirit level being put on to a plane which is known to be horizontal orvertical and then checked to ascertain whether the bubbles in thehorizontal and vertical measuring levels respectively are at the centreof the tube or spherical container.

The proposed spirit level has the following advantages over the knownspirit levels:

It is of a simple but nonetheless sturdy construction. It permitschecking of the inclination both of horizontal and also vertical planesin two directions. The proposed spirit level can also be used forsimultaneously vertically and horizontally aligning rectangular platesor panels such as for example cladding panels or panels for externalinsulation of buildings. It also permits measurement of angles andadjustment of planes which are inclined relative to the vertical or thehorizontal respectively. In addition, it can be used to check not onlythe position of a plane with respect to the vertical or horizontal butalso the spacing thereof from a reference plane or a reference point.

That plurality of functions is not afforded by any of the known spiritlevels.

The particular advantage of the first embodiment lies in the subdivisionof the spirit level into a central hinge portion 1 and four arms 9 whichare fixed to each other by means of a push-in fitment connection. Thataffords the possibility of varying the overall length of the spiritlevel by fitting arms 9 of different lengths on to the hinge portion 1.Long arms 9 may be necessary for example when a frame or another planewhich is not continuous has to be adjusted. The arms 9 then bridge overthe open portions thereof. A large number of conventional bar-likespirit levels 28 is already in use. The proposed spirit level of thesecond embodiment has the particular advantage that it permits thefurther use of conventional spirit levels 28.

Finally the particular advantage of the spirit level of the thirdembodiment lies in its simple construction. Its manufacturing costs arealso correspondingly low.

I claim:
 1. A spirit level comprising a pair of elongate arms which arepivotable relative to each other about a pivot axis and which have ameasuring device, for putting on to a plane and for detecting aninclination thereof,wherein each of the arms has a first and a secondlongitudinal portion with a rigid bend portion connecting them, alongitudinal axis of the first longitudinal portion of each arm isextended at a spacing parallel and in a plane from a longitudinal axisof the associated second longitudinal portion, the pivot axis extends inthe regions of the rigid bend portions of both arms, the firstlongitudinal portions of both arms are of a substantially equal firstlength and the second longitudinal portions of both arms are of asubstantially equal second length, and the arms are of such aconfiguration as to ensure that continous contact with the plane alwaysprevails both in a collapsed condition and also with any pivot anglebetween the arms.
 2. A spirit level according to claim 1 of wherein thefirst length is substantially equal to the second length.
 3. A spiritlevel according to claim 1 wherein the first and the second longitudinalportion of both arms is of a substantially equal width with respect tothe plane and the spacing of the longitudinal axes corresponds to saidwidth.
 4. A spirit level according to claim 1, wherein in the region ofthe bend portions the arms each have a respective recess which isprovided in a direction that is vertical with respect to the plane andwhich is of such a configuration that the arms can be fitted one intothe other, wherein the recess of an arm receives the bend portion of therespective other arm.
 5. A spirit level according to claim 4 wherein thepivot axis is afforded by an axis element and forms a central hingewhich connects both arms in the condition of being fitted one into theother, extending through a central point in the respective bend portion.6. A spirit level according to claim 1, wherein both arms are of thesame external shape.
 7. A spirit level according to claim 1 wherein, foreach of the arms first longitudinal portion, the bend portion and thesecond longitudinal portion are of an integral construction.
 8. A spiritlevel according to claim 1 wherein at least one of the arm is adapted tobe divisible along its longitudinal direction and an extension portioncan be fitted into such a division.
 9. A spirit level according to claim1 wherein at least one arm has at its end a device for fixing aconventional spirit level which extends the respective longitudinalportion of the arm.
 10. A spirit level according to claim 1 wherein, incross-section, the arms are each in the form of a U-shaped profile inthe region of the first and second longitudinal portions and areproduced by a die casting process.
 11. A spirit level according to claim1 wherein at predetermined locations the arms are provided withhorizontal recesses which are adapted for the insertion of levelelements.
 12. A spirit level according to claim 1 wherein an anglemeasuring device which is formed around the pivot axis and which can beread off in the condition of being put on a plane, for detecting anangle between the arms which are pivoted relative to each other in theplane.
 13. A spirit level according to claim 1 wherein a means isprovided in the region of the pivot axis for latchingly arresting thearms which are pivoted relative to each other, at least at onepredetermined angle.
 14. A spirit level according to claim 1 wherein acircular spirit level is disposed in the region of the pivot axis.
 15. Aspirit level according to claim 1 wherein at predetermined locations thearms are provided with vertical recesses which are adapted for theinsertion of level elements.
 16. A spirit level according to claim 1wherein, in cross-section, the arms are each in the form of a doubleT-shaped profile in the region of the first and second longitudinalportions and are produced by a die casting process.